Orthopoxvirus infection

正痘病毒属包含许多可在人类和动物中引起严重痘病的病毒，包括猴痘病毒（MPXV）、牛痘病毒（CPXV）和最著名天花病毒（VARV）。虽然经过历史性的全球疫苗接种运动，天花于1980年正式在世界范围内根除，但正痘病毒感染仍然是一个重大的公共卫生威胁。直到今天，多国猴痘疫情仍在继续。作为一种DNA病毒，MPXV理论上不会像RNA病毒那样频繁变异。然而、在近期猴痘疫情的基因组中新发现了适应性突变。因此，在全球猴痘疫情的背景下，不能排除MPXV进一步适应性突变并导致更大规模疫情爆发的可能性，我们迫切需要制定有效的治疗策略来对抗正痘病毒。迄今为止已经开发了多种治疗方法，包括抗病毒抑制剂、人牛痘免疫球蛋白（VIG）和痘病毒特异性单克隆抗体。越来越多的证据表明痘病毒抗体在病毒控制和原发和继发感染恢复中的重要性。治疗性单克隆抗体的开发代表了预防或治疗正痘病毒感染的有前途策略，目前靶向VACV A33、VACV B5、MPXV M1和VACV A27这四种原始蛋白的单克隆抗体在研究中表现出对几种正痘病毒（包括VACV、CPXV、MPXV和VARV）广泛的交叉中和活性。2024年3月27日，军事科学院邓永强、秦成峰研究团队联合艾博生物在Signal Transduction and Targeted Therapy上发表了题为“Rapid development of double-hit mRNA antibody cocktail against orthopoxviruses”的研究论文。本研究首次报告了具有体内保护作用的针对正痘病毒的mRNA抗体疗法，通过脂质纳米颗粒（LNP）封装的mRNA平台，构建了一组编码针对正痘病毒的广泛中和抗体的mRNA。单次静脉注射每种mRNA抗体均可在小鼠体内迅速产生有效的中和抗体。更重要的是，靶向EEV型和IMV型病毒的双打击（double-hit）mRNA抗体组合（Cocktail）Mix2a在小鼠中显示出对致命VACV攻击的卓越保护效力。编码正痘病毒抗体mRNA的构建和表征研究团队首先选择了四种经验证具有广泛交叉中和活性的抗体mAb22、mAb283、mAb26和mAb301，分别靶向VACV-A33、VACV-B5、MPXV-M1和VACV-A27蛋白。接着优化每种候选单克隆抗体的重链（HC）和轻链（LC）编码序列，并分别插入质粒ABOP-028中。制备所得的mRNA包含5'帽、5'UTR、信号肽、候选mAb密码子优化编码序列、3'UTR和poly(A)尾（图1a）。图1. 编码正痘病毒抗体mRNA的构建和表征LNP-mRNA体内表征将四种编码抗体的mRNA组合后包封为LNP制剂，分别为mRNA-mab22-LNP、mRNA-mab283-LNP、mRNA-mab26-LNP和mRNA-mab301-LNP。动态光散射分析显示粒径均匀，范围为73.12至75.39 nm，多分散系数（PDI）低于0.1。使用ELISA评估小鼠血清中的人IgG浓度，血清人IgG的浓度范围为269-2598 ng/mL（图2）。图2. LNP-mRNA体内表征为了进一步确定这些mRNA抗体是否有效，在BS-C-1细胞中使用VACV EEV和IMV进行了斑块减少中和试验（PRNT）。mRNA-mab22-LNP和mRNA-mab283-LNP注射小鼠的血清中测得高水平的抗EEV中和抗体而mRNA-mab26-LNP和mRNA-mab301-LNP注射有助于中和VACV的IMV形式，其中EEV候选药物的中和滴度远高于IMV候选药物，因此推测EEV候选药物对于卓越的保护效果至关重要。对VACV感染的保护效率由于肺组织是感染VACV的小鼠的主要感染器官，因此在BS-C-1细胞中使用标准斑块测定进一步测定了感染小鼠肺部的感染性病毒颗粒。用mRNA-mab22-LNP处理可完全控制肺部VACV复制，没有可检测到的传染性病毒颗粒。此外，使用H&E染色和免疫组化（IHC）分析对病理性肺部病变进行了研究。结果显示，VACV感染导致对照组小鼠上皮内膜轻度至显著弥漫性变性和坏死（黑色箭头），伴有出血、水肿（红色箭头）和纤维蛋白渗出到周围肺泡（蓝色箭头），而mRNA编码的抗体治疗（mRNA-mab283-LNP除外）显著阻止了VACV诱导的肺损伤（图3）。此外，使用抗VACV D8单克隆抗体进行的IHC分析显示，对照组小鼠肺中D8L蛋白阳性细胞，而mRNA抗体治疗组的肺组织中未检测到病毒蛋白阳性细胞。图3. 对VACV感染的保护效率研究双打击mRNA组合有助于实现卓越保护力为了确定中和IMV型和EEV型病毒的最佳双命中mRNA抗体混合物，相应地制备了两种候选药物，分别称为Mix2a（mRNA-mab22-LNP加mRNA-mab26-LNP）和Mix2b（mRNA-mab283-LNP和mRNA-mab26-LNP）实验显示，Mix2a和Mix2b有助于对EEV形式和IMV形式的VACV进行功能性中和，Mix2a产生的功能抗体水平高于Mix2b，两者都可以保护小鼠在感染致死剂量的VACV后免于体重减轻，完全阻止了VACV诱导的病理性肺部病变，通过IHC分析未检测到病毒蛋白阳性细胞。这些结果表明，对正痘病毒感染的最佳保护需要EEV和IMV靶向中和抗体的合作，并强调Mix2a是当前研究中最有效的双打击mRNA抗体组合候选物。图4. 双打击mRNA抗体组合有助于提高保护效率总结总体而言，单次注射mRNA抗体混合物Mix2a可防止小鼠感染正痘病毒。采用定制mRNA的人类抗体组合代表了一种很有前途的抗病毒策略，可以快速响应以对抗当前和未来的人类痘病毒爆发。需要注意的是，本研究制剂思路中，需要将编码轻链和重链的两个mRNA封装到LNP制剂中，而同源轻链和重链的正确配对对于抗体功能至关重要，这使得多组分mRNA抗体比多组分mRNA疫苗更为复杂。此外，研究发现，同时施用不同的mRNA表达抗体可能会导致功能性抗体的生产效率低下，Mix2a和Mix2b组的功能性抗体较单一抗体施用所获得的水平略低，存在一定抗体干扰问题。因此，需要进一步研究确定不同mRNA抗体间的相互作用以及对功能影响的具体机制。参考资料[1]Chi, H., Zhao, SQ., Chen, RY.et al. Rapid development of double-hit mRNA antibody cocktail against orthopoxviruses. Sig Transduct Target Ther 9, 69 (2024). https://doi.org/10.1038/s41392-024-01766-8识别微信二维码，添加生物制品圈小编，符合条件者即可加入生物制品微信群！请注明：姓名+研究方向！版权声明本公众号所有转载文章系出于传递更多信息之目的，且明确注明来源和作者，不希望被转载的媒体或个人可与我们联系(cbplib@163.com)，我们将立即进行删除处理。所有文章仅代表作者观点，不代表本站立场。

As the monkeypox outbreak continues in the United States and other parts of the world, researchers and public health officials scramble to test known drugs against the disease. For that and more research stories, continue reading. Tecovirimat Appears Safe and Effective Against Monkeypox A research study out of the University of California-Davis Health found tecovirimat (TPOXX) overall safe and effective to treat monkeypox symptoms and skin lesions, but researchers will still proceed with caution. The antiviral drug is approved to treat smallpox, which was eradicated globally in 1980. TPOXX inhibits the protein involved in the release of the enveloped virus. The CDC allowed doctors to prescribe TPOXX for compassionate use for adults and children with orthopoxvirus infections, including monkeypox. The new study evaluated 25 patients with monkeypox who received TPOXX. They published their research in the journal JAMA. “We have to be very careful in how we interpret the data,” George Thompson, M.D., co-author and professor at the UC Davis School of Medicine, Department of Internal Medicine, Division of Infectious Diseases, and the Department of Medical Microbiology and Immunology, said. “It is hard to differentiate the side effects due to therapy from those caused by the infection.” The recent monkeypox outbreak has led to more than 45,500 cases, as of Aug. 22. Typically, symptoms resolve on their own in two to four weeks, although up to 13% of patients require hospitalization. The patients in the study were referred to UC Davis Medical Center, primarily via the Sacramento County Department of Public Health. Patients were offered the drug if they had skin lesions on multiple body parts or sensitive areas such as the face or genital region. By Day 7, 40% of patients’ lesions had healed. By Day 21, 92% reported being healed and pain-free. On average, the patients had symptoms or lesions for 12 days before initiating antiviral therapy. “Polypill” Cuts Cardiovascular Death by 33% After a Heart Attack Investigators at The Mount Sinai Hospital and Mount Sinai School of Medicine found that a three-drug “polypill” prevented secondary adverse cardiovascular events in people who previously had a heart attack and cut CV deaths by 33%. The drug was developed by the Spanish National Center for Cardiovascular Research (CNIC) and Ferrer and was tested in the Phase III SECURE trial. The three drugs in the pill are aspirin, ramipril and atorvastatin. Standard therapy after a heart attack includes an antiplatelet drug such as aspirin, ramipril or another drug to control blood pressure and a lipid-reducing drug like a statin. However, patient compliance is around 50%. The study evaluated the polypill to determine if the improved adherence led to a decrease in CV events, which it did. The polypill is commercially sold under the name Trinomia. How Astrocytes Contribute to Brain Disorders Scientists at the Salk Institute have identified a molecule, insulin-like growth factor (IGF), that can reduce disease symptoms in mice with neurodevelopmental disorders such as Rett, Fragile X and Down syndromes. The molecule is produced by astrocytes, a special type of brain immune cells that interfere with normal brain cell development in several neurodevelopment disorders. Astrocytes are star-shaped glial cells that outnumber neurons by a factor of five and are responsible for holding nerve cells in place and helping them develop and function properly. The researchers isolated astrocytes and neurons from the developing brains of mice with genetic mutations that cause Rett, Fragile X and Down syndrome. They then evaluated the levels of 1,235 different proteins produced by each type of astrocyte. In each disease, they found hundreds of proteins at higher or lower levels, with 120 common to all three. Their studies found that all astrocytes impacted by the three syndromes had a high level of Igfbp2, a protein that blocks IGF. The neurons make enough IGF, but it can’t get where it needs to be because the molecules astrocytes produce interfere with it. Excess Igfbp2 produced by astrocytes slows the growth of neurons. By blocking Lgfbp2 in mice with Rett syndrome, symptoms of the disease decreased. The researchers note that they have a long way to go before turning this discovery into a therapeutic, but the finding may lead to several new approaches to neurological diseases. Blocking Key Enzymes Can Boost T-Cell Responses in Cancer Immunotherapy A team of researchers at Louisiana State University Health New Orleans identified a vital immunosuppressive pathway and a promising approach to protecting T-cells’ ability to attack cancer cells. Immune cells that attack and kill cancer cells are called CD8 T-cells. To be effective, CD8 T-cells need a protein called NOTCH1. NOTCH1 is weakened by a compound, adenosine, produced by cancer cells. The research team worked with a Massachusetts biotech company, Nimbus Therapeutics, to test a CBL-B inhibitor, which, when used with existing immunotherapeutics, significantly increased the potency of the immunotherapy. The CBL-B inhibitor prevented NOTCH1 degradation in response to adenosine, which improved CD8+ T-cell effector functions, anti-cancer response and immunosuppression resistance. Long Covid Rare in Kids, But More Common than Hospitalization Researchers from the National Institutes of Health found that the incidence of Long COVID was lower in kids than in adults, but that more kids had Long COVID than kids who were hospitalized with acute COVID-19. The researchers used RECOVER Pediatric Electronic Health Records Cohort, and the study was authored by Suchitra Rao, M.D. with Children’s Hospital Colorado. There was overlap with adults regarding Long COVID and hospitalization, but Long COVID included some unique features in children, such as the risk of the inflammatory syndrome PASC. The study examined electronic health record data from 659,286 children who were tested for SARS-CoV-2 and compared 59,893 children who tested positive with those who tested negative. “We concluded that many of the symptoms children experience post-COVID-19 are similar to what is seen in adults, but there are some features more unique to children, such as myocarditis, abnormal liver enzymes, hair loss, skin rashes and diarrhea,” Rao wrote.

Researchers have published one of the earliest studies assessing the use of tecovirimat to treat monkeypox symptoms and skin lesions. The antiviral drug approved for smallpox treatment appeared to be safe and effective in 25 patients with monkeypox (MPX). A UC Davis Health study finds that the antiviral tecovirimat appears to be safe and effective for the treatment of monkeypox symptoms and skin lesions. The study is one of the earliest studies to assess and report the outcomes of treating patients with monkeypox with this antiviral. Tecovirimat (TPOXX) is an FDA-approved antiviral drug for the treatment of smallpox. It limits viral spread in the body by inhibiting the work of the protein involved in the release of the enveloped virus. Recently, the Centers for Disease Control and Prevention (CDC) allowed physicians to prescribe tecovirimat on a compassionate use basis to treat adults and children with orthopoxvirus infections, including monkeypox. In a research letter published in JAMA, UC Davis infectious disease experts presented insights on 25 patients with monkeypox who were given tecovirimat therapy. "We have very limited clinical data on the use of tecovirimat for monkeypox infection. There is much to learn about the natural progression of the disease and how tecovirimat and other antivirals may affect it," said lead author Angel Desai. She is an adult infectious disease specialist at UC Davis Health. Treating monkeypox with tecovirimat The recent global outbreak of monkeypox has led to more than 45,500 cases as of August 22, 2022. While symptoms usually resolve on their own in 2-4 weeks, a recent study showed that 13% of patients needed hospitalization. The new study included patients referred to UC Davis Medical Center, primarily through the Sacramento County Department of Public Health, between June 3 and August 13, 2022. Patients with skin lesions in multiple body parts or in sensitive areas such as the face or genital region were offered oral tecovirimat treatment. The treatment was weight-based, given every 8 or 12 hours, and was taken within 30 minutes of a high-fat meal. The researchers collected clinical data at the first in-person evaluation for treatment and by in-person or telephone interview on day 7 and day 21 following the beginning of therapy. In total, 25 patients with confirmed monkeypox infection completed a course of tecovirimat therapy. All were male. Their age ranged between 27 and 76 years (the median age was 40). Nine patients had HIV. Only one patient had the smallpox vaccine (taken more than 25 years ago) and four others received a dose of JYNNEOS vaccination after symptoms started. Symptoms in patients with monkeypox, MPX The study found that 92% of patients had lesions in their genital or anal area. While all patients had painful lesions, around half had fewer than 10 lesions over their entire body. On average, the patients had symptoms or lesions for 12 days before they started their antiviral treatment. Fever was the most common symptom (76% of the patients), followed by fatigue (32%), sore throat (20%) and chills (20%). Other symptoms included backache (12%), muscle pain (8%), nausea (4%) and diarrhea (4%). All patients completed the tecovirimat therapy and tolerated their treatment well. They were treated for two weeks, except for one patient who was treated for 21 days. On day 7 of therapy, 40% of patients had healed from their lesions. By day 21, 92% had healed and were pain-free. The most reported adverse events on day 7 of therapy included: fatigue (28%), headache (20%), nausea (16%), itching (8%) and diarrhea (8%). "We have to be very careful in how we interpret the data. It is hard to differentiate the side effects due to therapy from those caused by the infection," said infectious diseases expert and co-author George Thompson. Thompson is a professor at the UC Davis School of Medicine in the Department of Internal Medicine, Division of Infectious Diseases, and the Department of Medical Microbiology and Immunology. The study was small and did not include a control group. So, assessing antiviral efficacy in terms of symptom duration and severity was limited. Also, the time from symptom onset to starting the antiviral therapy varied among the patients. The researchers called for large-scale studies to explore antiviral efficacy dosing and adverse events. Coauthors on this study are Sonja Neumeister, Anna Arutyunova, Katelyn Trigg and Stuart H. Cohen.